China’s island-building activities at the South China Sea are the biggest source of tension and uncertainty for the Association of Southeast Asian Nations (Asean), according to former Foreign secretary Albert del Rosario.

Del Rosario, one of the speakers at the forum organized by the US Embassy and the Center for Strategic and International Studies (CSIS) titled US-Asean Relations: Charting the Next 40 years, said Asean, which is composed of Thailand, Vietnam, Indonesia, Singapore, Malaysia, Myanmar, Cambodia, Laos, Brunei, and the Philippines, has grown and become more coherent but its solidarity and resolve continue to be tested by tensions and challenges.